Ash I liked your page, I think you have balls of British steel mate, enthusiasm is fantastic experience takes time. But as others have said, don't run before you can walk. I wish you well, as my career in tiling is coming to an end yours is just starting you have my mobile no.
I have a Karcher K2 and its been fine for over 5 years. Neighbour has a bigger one for his MX bikes but he leaves it in the cold garage over winter. If he uses it before it thaws out you can break parts inside.
Anyway no problems with mine but looking at buying a drive cleaner for it now.